Seasonal variation in carbon cycling in a Bornean tropical rainforest

2019 Fiscal Year Final Research Report

• Project/Area Number: 15K07467
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Forest science
• Research Institution: Kyushu University
• Principal Investigator: Katayama Ayumi 九州大学, 農学研究院, 助教 (70706845)
• Project Period (FY): 2015-04-01 – 2020-03-31
• Keywords: 熱帯雨林 / 呼吸 / NPP / 乾燥 / フェノロジー

Outline of Final Research Achievements

Little is known about seasonal variation in carbon cycling with tree phenology in lowland Bornean tropical rainforests where there is little seasonality in temperature and precipitation. The objective of this study is to know how respiration and production of root and stem change with soil water availability.
Woody tissue respiration was positively related with soil water content. Stem growth was different among tree species, but stem growth was low in severe dry period and high in wet period for most tree species. LAI was also increased with soil water content. On the other hand, soil respiration and fine root respiration and biomass were not related to soil water availability. These results imply that seosonal variation in carbon cycling in this forest is relatively conservative even though there is clear phenology for some tree species with soil water availability.

Free Research Field

森林科学

Academic Significance and Societal Importance of the Research Achievements

気候変動の将来予測などを行ううえで、熱帯雨林の炭素循環の理解は必要不可欠であるが、特に気象の季節性が不明瞭というアマゾンなどとは異なる特徴を持つアジア熱帯雨林において、森林の中のどこで、いつ、どのくらいのCO2がで蓄積・放出されるのかといった中身についての理解は進んでいないという問題点があった。本研究はアジア熱帯雨林で初めて、森林の炭素循環の各要素について長期間測定を行い、森林全体の炭素循環としてはあまり時間的な変化はないことを示した。この成果は、炭素循環モデリングでの精度向上など、今後の将来予測を行う際に非常に意義深いデータとなると考えられる。